<svg xmlns="http://www.w3.org/2000/svg">
  <defs>
    <linearGradient id="grad1" x1="0" y1="0" x2="1" y2="0">
      <stop stop-color="yellow" offset="0"/>
      <stop stop-color="blue"   offset="1"/>
    </linearGradient>
  </defs>
  <rect x="10" y="10" width="200" height="80" fill="url(#grad1)"/>
</svg>
